Is it mutar to qoute half of a pasuk or to paraphrase a pasuk in a speech? Thank You
Yes, it is permitted to quote or paraphrase a pasuk.
We find in countless places in Chazal that half-pesukim are quoted, and therefore it is clear that there is no prohibition on quoting half a pasuk (though the basic prohibition is mentioned by the Magen Avraham 51:9).
Some explain that the main prohibition applies only for readings in public (though see Berachos 4).
A further possibility is that the prohibition only applies in Torah learning (Zecher Yehosef no. 38), but not in regular speech or quotation.
For a detailed analysis see Tzitz Eliezer 19:7.
It is also possible that the prohibition applies specifically to causing the verse to be deformed by skipping words – citing the beginning and the end without the middle.